Method and apparatus for elasticity imaging

Abstract

A computational efficient algorithm for compression analysis of free-hand static elasticity imaging performed using medical diagnostic ultrasound imaging equipment offers tissue compression quality and quantity feedback to the operator. The algorithm includes a criterion for automatic selection of the most advantageous pre- and post- compression frame pairs delivering elasticity images of optimal dynamic ranges (DR) and signal-to-noise ratios (SNR). The use of the algorithm in real time eases operator training and reduces significantly the amount of artifact in the elasticity images while lowering the computational burden.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a computational efficient algorithm for tissue compression analysis for free-hand static elasticity imaging. More specifically, this invention relates to an elasticity imaging system that employs medical diagnostic ultrasound imaging equipment to produce strain images. [0003] 2. Description of Related Art [0004] It has been proved that pathological conditions often produce changes in biological tissue stiffness. Tumor tissues, for example, are known to exhibit mechanical properties different from the surrounding tissue, as indicated by the use of palpation as a diagnostic tool. Breast and prostate tumors are especially susceptible to changes in mechanical properties, as indicated in an article by T. A. Krouskop, T. M. Wheeler, F. Kallel, B. S. Garra, and T. Hall, entitled “Elastic moduli of breast and prostate tissues under compression.”, Ultrasonic Imaging, 20:260-274, 1998, which i...

AI Technical Summary

Problems solved by technology

It has been proved that pathological conditions often produce changes in biological tissue stiffness.

However, a lesion may or may not possess echogenic properties that would make it detectable with conventional diagnostic ultrasound imaging systems.

As the boundary conditions and the modeling of theory of elasticity are highly dependent on the structure of the biological tissue, the implementation of the last step is rather cumbersome and typically not performed.

However, real-time elasticity imaging is indeed needed to acquire and process the ultrasonic echo data in such a way that patient-scanning time is relatively low and diagnostically relevant elasticity images are produced immediately during the scan.

Furthermore, the real-time processing of the ultrasonic echo data allows for freehand compression and scanning of the biological tissue rather than utilizing bulky and slow motorized compression fixtures.

Its disadvantage, however, consists of exhaustive operator training, as the sonographer constantly needs to adjust the compression technique to obtain strain images of good quality.

In short, due to the extremely complex nature of the tissue compression, obtaining elasticity images of consistent quality using free-hand strain imaging is neither trivial nor as expeditious as obtaining good quality B-mode images, thus real-time compression feedback is necessary to ensure proper operator training.

However, those implementations disclosed by the '768 patent and the Zhu et al. and Shiina et al. articles do not account completely for all the limitations mentioned above.

More particularly, neither the articles by Zhu et al. and Shiina et al. nor the teachings of the '768 patent provide a quantitative indication of the compression quality being achieved by the operator.

Moreover, the operator does not receive guidance in order to improve the compression quality when s / he is only provided strain images that may contain artifacts and poor SNR.

One of several drawbacks being that possible artifacts present in the strain image cannot be qualitatively linked to poor compression quality.

Therefore the computational burden placed upon the imaging system is extremely high while only select sets of strain images faithfully indicate the mechanical properties of the imaged tissue and are artifact-free.

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